1. Field of the Invention
The invention relates to a switch assembly, more particularly to a switch assembly for use in a coin collector of a public telephone or an automatic vending machine.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional switch assembly is adapted to be fixed within a coin collector of a public telephone or an automatic vending machine and includes a switch housing 10, a rotary lever 141, a coiled spring 143, a mounting ring 19, a rotating unit 12, and a limiting device.
As illustrated, the switch housing 10 has a first contact 15 and a second contact 16 installed therein, and an opening 10A formed through a wall of the housing 10. As illustrated, the left end of the rotary lever 141 is biased by the spring 143 to locate at a pivot point in a recess of the wall of the housing 10, so that the rotary lever 141 is rotatable between an open position in which a movable lever 142 coupled with the rotary lever 141 by the spring 143 contacts electrically the first contact 15, and a closed position in which the movable lever 142 contacts electrically the second contact 16. The spring 143 biases the rotary lever 141 to rotate in a direction in the housing 10 so that the movable lever 142 contacts the second contact 16. The mounting ring 19 is fixed within the opening 10A formed through the wall of the housing 10. The rotating unit 12 includes a rotating shaft 120 journalled within the ring 19, a push plate 121 formed integrally with the inner end portion of the shaft 120, and a radially extending push needle 11 mounted securely on the outer end portion of the shaft 120. The limiting device includes a limiting metal plate 122 which is secured to the outer end portion of the shaft 120 and which has a stop element 123 projecting integrally and outwardly from the periphery of the plate 122. The stop element 123 is movable between two projections 181 which are provided on the wall of the housing 10.
Referring to FIGS. 1, 2 and 3, the push needle 11 can be struck and rotated by a coin dropped from an upper end portion of the coin collector so that the push plate 121 rotates the rotary lever 141. Rotation of the rotary lever 141 moves the movable lever 142 away from the second contact 16 to contact the first contact 15.
During assembly, after being placed into the housing 10 through the ring 19, the push plate 121 is rotated in the housing 10 so as to be deflected from the radial extension 191 of the central bore 190 of the ring 19, thereby preventing separation of the shaft 120 from the ring 19.
The stop element 123 is then pressed and bent toward the wall of the housing 10 by means of a hammer, in order to move from the straight position of FIG. 4 to the bent position of FIG. 5 so as to limit the stop element 123 between the projections 181. In this way, the push plate 121 (see FIG. 2) rotates the rotary lever 141 between the open position and the closed position. It requires special skill to hammer the stop element 123 into the bent position, thereby resulting in inconveniences during assembly.